(a) Field of the Invention
The present invention is related to a packaging technology of electronic device, and more particularly to an electronic device provided with electro magnetic interference (EMI) protection circuit and packaging technology thereof.
(b) Description of the Prior Art
In a design of digital circuitry, conduction wire and circuit board radiate electromagnetic waves to affect layout of circuitry and wire in the perimeter of the circuit and any conductor that may transmit these electro magnetic (EM) waves, a phenomenon known as EMI. So far there is no way to absolutely exclude EMI; but hazards from EMI may be minimized by good circuit design and wiring technique for the circuit board.
For example, grounding, screening, and filtering methods may be employed to complete EM compatibility design. Wherein, the grounding method involves leading interference signals into a grounding end; screening, a screen material to resist EMI; and filtering, an EMI filter to stop interference signals.
All these three EMI preventive methods are the most common practices used for all electronic devices to prevent EMI. However, angling at the electronic device (electric installation), the means to prevent EMI is comparatively passive since its EMI preventive strategy must rely upon its EMI protection mechanism. Furthermore, EMI is essentially originated from excessive distribution density of electronic devices or from HF circuit. As the development of electronic products is heading for HF and smaller size; whether an electronic product is provided with sufficient space to build EMI protection mechanism justifies further discussion.